a. Field of the Invention
The present invention relates to an infusion pump for administering controlled doses of a fluid, notably to an ambulatory infusion pump for administering fluid medicament to a patient.
It can be advantageous to provide a patient with small doses of a medicament over a long period of time, rather than administering a comparatively large dose by a single injection. For example, medicaments such as insulin for diabetics are more effective when administered in this manner, and particularly if the dosage can be adjusted automatically in response to changes in blood glucose levels. An ambulatory infusion pump is worn by a patient and can provide for such an improved dosing regime.
b. Related Art
WO 2004/024218 describes an infusion pump comprising a reservoir for storing a liquid agent, and a drive mechanism for propelling a piston towards an outlet from the reservoir in order to discharge the agent. The drive mechanism permanently forces the piston forwards, and a locking mechanism is provided for permanent locking of progress of the piston. The locking mechanism is released by operation of an escapement mechanism under electronic control for discharge of the agent.